Loans and Allowance for Credit Losses on Loans - Loans Held for Investment by Portfolio Segment (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 20,420,816,000	$ 19,350,920,000
Unearned income (net of direct origination costs)	(80,258,000)	(63,580,000)
Total loans held for investment	20,340,558,000	19,287,340,000
Allowance for credit losses on loans	(249,973,000)	(253,469,000)	$ (211,866,000)
Loans held for investment, net	20,090,585,000	19,033,871,000
Loans held for sale	44,105,000	36,357,000
Interest receivable	118,100,000	100,400,000
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	10,410,766,000	9,832,676,000
Allowance for credit losses on loans	(171,437,000)	(185,303,000)	(154,360,000)
Loans held for sale	43,399,000	36,357,000
Mortgage finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,978,328,000	4,090,033,000
Allowance for credit losses on loans	(4,173,000)	(10,745,000)	(6,083,000)
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	5,500,774,000	4,875,363,000
Allowance for credit losses on loans	(71,829,000)	(54,268,000)	(48,247,000)
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	530,948,000	552,848,000
Allowance for credit losses on loans	(2,534,000)	(3,153,000)	$ (3,176,000)
Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale	$ 706,000	$ 0